JP2572436B2 - Fluid pressure servo valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo valve capable of controlling a flow rate by an external signal.

[Conventional technology]

In a conventional servo valve for controlling a flow rate, a guide valve is formed in a spool shape, and the spool-shaped guide valve performs control by performing a linear reciprocating motion only in the left and right directions by fluid pressure.

However, in the conventional servo valve, the guide valve performs a linear reciprocating motion only in the left-right direction as described above. Therefore, when the guide valve is mounted on a vehicle or the like having a large vibration, this vibration is generated in the motion direction of the guide valve. If it works, the guide valve will move on its own, causing a problem that accurate flow control cannot be performed.

Further, in Japanese Utility Model Laid-Open No. 62-126672, the flow rate is controlled by directly rotating a valve by a motor. In such a motor valve, the motor receives the fluid pressure directly through the valve, and when the valve is driven, the rotational torque must be higher than the fluid pressure.
The required current value increases and the size of the motor also increases. Further, there has been a problem that the response is very poor.

Further, Japanese Patent Publication No. 37-11321 discloses a pressure difference between a pair of pressure chambers defined between a middle cylinder and a main rotary valve.
A dual rotation type servo valve controlled by an auxiliary rotary valve arranged concentrically with the rotary valve is described.

In this case, at the position where the main rotary valve rotates,
In order to maintain the position, the suction force of the auxiliary rotary valve to the exciting coil, which generates the rotational force, and the pressure difference generated to rotate the main rotary valve are directly balanced. This required a large exciting force enough to directly balance the pressure difference required to rotate the valve, and the driving means and the like had been increased in size.

[Problems to be solved by the invention]

Therefore, an object of the present invention is to provide a small and highly responsive servo valve that can accurately control the flow rate even when receiving vibration.

[Means for solving the problem]

Therefore, in the present invention, a housing provided with at least a pressure port, a control port, and a return port, a guide valve provided in the housing, and controlling the communication between the ports by rotational driving, the housing and the guide valve And is communicated with the pressure port, and at least one pair of pressure chambers that rotationally drives the guide valve by fluid pressure from the pressure port; and that communication between the return port and the pair of pressure chambers is performed. A pilot valve for controlling the pressure of the pair of pressure chambers by rotating a predetermined angle by a driving means driven by an external signal, and controlling the pressure of the pair of pressure chambers. While rotating according to the pressure difference of the pressure chamber, the pilot valve is Inner valve is one which employs a technical means of controlling the pressure of said pair of pressure chambers so as to rest by the pressure of the pair of pressure chambers at a predetermined rotational angular position is substantially balanced.

[Operation] By adopting the above technical means, when the guide valve is rotated to a predetermined rotation angle position after the guide valve is rotated by a predetermined pressure difference, the pressures of the pair of pressure chambers are substantially balanced. The communication with the pressure chamber is controlled by the pilot valve. Therefore, there is no direct relationship between the rotational force for maintaining the guide valve at a certain angular position and the driving force of the pilot valve, and the driving means is required to control the communication with the pressure chamber from the pilot valve to the pressure chamber. Only torque is generated.

〔Example〕

FIG. 1 shows a sectional view of a servo valve of the present invention. Reference numeral 10 denotes a torque motor unit, and its detailed structure is shown in FIG. 2 as viewed from the direction of arrows AA in FIG. The torque motor unit 10 is provided with an armature 11, and the armature 11 is rotatable about the inner cylindrical hollow portion 14 of the two coils 12, 13 facing the armature 11 with D as an axis. Further, the outer peripheral portions of the coils 12 and 13 are fixed to a yoke 16, and a permanent magnet is provided above the yoke 16 as shown in FIG.
17 are provided.

The upper part of the pole piece 18 of the yoke 16 is N
(S), S (N) is attached to the lower side, and N and S poles are generated at the left and right ends of the armature 11 when the coils 12 and 13 are energized. Attraction and repulsion are generated.

Further, as shown in FIG. 1, a rotation angle sensor 21 is mounted above a cover 20 surrounding the torque motor section 10, and a shaft section 15 thereof passes through a hole provided in the cover 20, and a pilot section of the valve section 30 is provided. The pilot valve 31 is fixed to an upper portion of the shaft of the valve 31 and rotates integrally with the pilot valve 31.

In FIG. 2, reference numeral 25 denotes an equilibrium spring, one end of which is in contact with the armature 11 and the other end of which is in contact with the adjusting screw 26.
Generates a reaction force with respect to the rotational torque. Adjustment screw 26
By rotating, the neutral position of the armature 11 can be adjusted.

FIG. 3 is a view taken in the direction of arrows BB in FIG. 1, and shows the detailed structure of the valve section 30.

The guide valve 100 of the valve section 30 is a rotary type guide valve that has a substantially disk shape and that rotates and reciprocates around D as an axis.
The rotary valve section 30 receives the fluid supplied from the pressure ports 70a and 70b, which are fluid passages, through a pipe 32.
a, 32b, 33a, 33b and further through orifices 34a, 34b, 35a, 35b to conduits 36a, 36b, 37a, 37b for nozzles 38a, 38b, 39a, 39b
And has a flow channel that flows out of the cylindrical hole 40 as a return portion. One end of each of the pipes 36a, 36b, 37a, 37b is a guide valve 1.
Pressure chamber 41a, 41b, 42a, 42b composed of 00 and housing 71
Is open to each. And lands 50a, 50b, 51
a, 51b, 52a and 52b are formed. Fig. 4 is a guide valve
FIG. 5 is a view taken along the line CC in FIG. 1 of FIG. 1, and as shown in FIG.
A conduit 65 for guiding the fluid to 0a and 60b is formed. Here lands 50a and 50b, 51a, 51b, 52a and 52b, pressure port 70a,
70b, pressure chambers 41a and 41b, 42a and 42b, pipelines 32a and 32b, 33a and 33b,
36a and 36b, 37a and 37b, and the orifices 34a and 34b, 35a and 35b, and nozzles 38a and 38b, 39a and 39b of these conduits have a point 0.
, And each is a pair of the same size and the same shape. Further housing
The control ports 72a and 72b and the return ports 60a and 60b of the 71 are also located at point-symmetrical positions about the point 0, and have the same size and the same shape as the pressure ports 70a and 70b.
Pilot valve 31 is a hole 4 drilled in rotary guide valve 100.
0, and the upper end is the torque motor 10
Is fixed to the armature 11 and a small reciprocating rotation is performed integrally with the armature 11 around the axis D by the permanent magnet 17 and the coils 12 and 13.

Edge portion of pilot valve 31 in neutral state
75a, 75b, 76a, and 76b are located at positions corresponding to the respective axes of the nozzles 38a, 38b, 39a, and 39b.

Reference numerals 80a and 80b denote neutral springs for holding the guide valve 100 in a neutral state when there is no input signal.
And a housing 71, and is inserted into a fixing hole (not shown). 85 is a filter unit.

The operation of the rotary servo valve will be described below by taking a three-way valve as an example.

A magnetic polarity is given to the armature 11 by passing an input current through the coils 12 and 13, and the armature 11 is minutely rotated about D by the magnetic attraction and repulsion between the armature 11 and the pole piece 18. The rotational force at this time is proportional to the input current, and stops at a position balanced with the restoring force of the balance spring 25. Since the upper end of pilot valve 31 is fixed to armature 11, the rotation angle of armature 11 is equal to the rotation angle of pilot valve 31.

FIG. 5 is a cross-sectional view showing a case where the pilot valve 31 is rotated counterclockwise by θ. The edge portions 75a and 75b of the pilot valve 31 reduce the opening areas of the nozzles 38a and 38b, respectively. Portions 76a and 76b increase the opening area of nozzles 39a and 39b, respectively. As a result, the pressure chambers 41a and 4
The pressure in 1b increases and the pressure in pressure chambers 42a and 42b decreases.
For this reason, a pressure difference is generated between the pressure chambers 41a, 41b and 42a, 42b, and this pressure difference causes the rotary guide valve 100 to rotate counterclockwise. The rotation of the guide valve 100 causes the nozzle 38a to rotate.
The opening area of the nozzles 39a and 39b starts to increase, and the opening area of the nozzles 39a and 39b starts to decrease. And finally the nozzles 38a, 38
When the opening areas of b, 39a and 39b become equal, the pressure difference 41a, 41b,
The pressures at 42a and 42b become equal, and the guide valve 100 stops at this position. The state is shown in FIG. The pilot valve 31 is rotated by the rotation angle θ. However, here, the reaction force of the neutral springs 80a and 80b, the fluid reaction force acting on the guide valve 100, and the like are ignored. Guide valve 100
Is rotated by θ, the control port 72a
And 72b have openings corresponding to θ, and flow rates corresponding to the openings flow from the pressure ports 70a and 70b into the control ports 72a and 72b, respectively. At this time lands 50a and 5
0b, 51a and 51b, 52a and 52b, orifices 34a and 34b, 35a and 35b,
Since the nozzles 38a and 38b and the nozzles 39a and 39b are located at point symmetric positions with respect to the point 0, no load is applied in the radial direction of the guide valve 100 due to the asymmetry of the fluid pressure. Here, the direction of the input current is switched,
If the pilot valve 31 is rotated clockwise by reversing the magnetic properties of 11, the guide valve 100 is also rotated clockwise following this, and the flow rate according to this rotation angle is transmitted from the control ports 72a, 72b. It flows into the return ports 60a and 60b, respectively. If the input current is set to 0, the balance spring
25 and neutral springs 80a, 80b, pilot valve 31,
The guide valve 100 returns to the neutral point. Here, the flow rate proportional to the rotation angle of the guide valve is transferred from the pressure ports 70a, 70b to the control ports 72a, 72b or the control port 7a.
If the shape of the port is determined so that it flows from 2a, 72b to the return ports 60a, 60b, the rotation angle of the armature 11 can be made proportional to the input current, so that the rotation angle of the guide valve 100 proportional to the input current is eventually obtained. Thus, an output flow rate proportional to the rotation angle can be obtained.

FIG. 7 shows a rotary hydraulic servo valve (three-way valve) of the present invention.
An example of a control circuit using the above will be described. In this embodiment, the position of the load 300 is determined by the actuator (hydraulic piston cylinder) 200. Now, when a position design signal is applied from the control signal generator 210 to the input terminal 220 of the control system, the current position of the load is detected by the detector 230, and this is compared with the position setting signal as a feedback signal. This produces an error signal. The error signal is amplified by the amplifier 240 and an error current flows through a coil of a torque motor (not shown) of the electrohydraulic servo valve 250. This allows the electrohydraulic servo valve 250
Operates to supply a hydraulic pressure proportional to the error current by the pump 262 to the actuator (hydraulic piston cylinder) 200 from a hydraulic supply source 260 composed of a tank 261 and a pump 262. Thus, the hydraulic piston cylinder 200 is controlled and driven to move the load 300 connected to the piston shaft to a target position.

FIG. 8 shows a second embodiment of the present invention. As shown in FIG. 8, pressure ports 201a and 201b, first control ports 202a and 202b, second control ports 203a and 203b, return ports 204a and 204b, and conduits 205a and 205b are provided. This is a four-way rotary servo valve. The operation principle is the same as that of the three-way valve of the first embodiment.

〔The invention's effect〕

By adopting the present invention, after the guide valve is rotated by the predetermined pressure difference, when the guide valve is positioned at the predetermined rotation angle position, the pilot valve is moved to the pressure chamber so that the pressure in the pressure chamber is substantially balanced. Is controlled. Therefore, the rotational force for maintaining the guide valve at a certain angular position is reduced as compared with the conventional case, and the driving means only needs to generate the torque necessary for controlling the communication with the pressure chamber to the pilot valve. Can be reduced in size and the responsiveness can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a view taken along the line AA in FIG. 1, and FIG. 3 is B in FIG.
FIG. 4 is a view taken in the direction of the arrows CC in FIG.
5 and 6 are sectional views showing the operation of the first embodiment of the present invention, FIG. 7 is a hydraulic circuit diagram using the present invention, and FIG.
FIG. 5 is a sectional view showing a second embodiment of the present invention. 10 Torque motor section (rotation drive means), 31 Pilot valve, 41, 42 Pressure chamber, 71 Housing, 100 Guide valve.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Nobuo Hiraiwa, 1st Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Takayuki Katsuta 1st Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation ( 56) References: Japanese Utility Model Showa Sho 62-126673 (JP, U) Japanese Patent Publication No. 37-11321 (JP, B1)

Claims (1)

(57) [Claims] A housing provided with at least a pressure port, a control port, and a return port; a guide valve provided in the housing, for controlling communication between the ports by rotational driving; and the housing and the guide valve. And is communicated with the pressure port, and at least one pair of pressure chambers that rotationally drives the guide valve by fluid pressure from the pressure port; and that communication between the return port and the pair of pressure chambers is performed. A pilot valve for controlling the pressure of the pair of pressure chambers by rotating a predetermined angle by a driving means driven by an external signal, and controlling the pressure of the pair of pressure chambers. While rotating and moving according to the pressure difference of the pressure chamber,
The fluid pressure servo valve, wherein the pilot valve controls the pressure in the pair of pressure chambers so that the guide valve is stationary when the pressures in the pair of pressure chambers are substantially balanced at a predetermined rotation angle position. .